public ValueAndModified computeValueAndModified(ValueTuple vt) { int source_mod = base.getModified(vt); if (source_mod == ValueTuple.MISSING_NONSENSICAL) return ValueAndModified.MISSING_NONSENSICAL; if (source_mod == ValueTuple.MISSING_FLOW) return ValueAndModified.MISSING_FLOW; return computeValueAndModifiedImpl(vt); }